scheduling algorithm to not schedule same RPA on the same node

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Description

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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PR Type

Enhancement

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Description

• Enhanced slot selection algorithm to avoid RPA conflicts.

• Added detailed logging for debugging slot selection process.

• Introduced doesNotConflictWithExistingRpaType method for RPA conflict checks.

• Improved node and slot filtering with additional conditions.

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Changes walkthrough 📝

Relevant files

Enhancement

DefaultSlotSelector.java Enhanced slot selection algorithm and added logging            java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java Enhanced slot selection to avoid scheduling same RPA on the same node. Added logging for debugging node and slot evaluations. Introduced doesNotConflictWithExistingRpaType method for RPA conflict checks. Refactored sorting and filtering logic for better maintainability. +97/-44

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[qodo-merge-pro]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Logging Level The code uses WARNING log level for informational messages that are not warnings. Consider using INFO or FINE level for debug messages to avoid polluting logs. LOGGER.log(Level.WARNING, "Capability {0}", name); } LOGGER.log(Level.INFO, "Requested RPA Type: {0}", requestedRpaType); Null Check The requestedRpaType comparison in doesNotConflictWithExistingRpaType() could throw NullPointerException if requestedRpaType is null. Consider adding null check. boolean conflict = requestedRpaType.equals(existingRpaType);

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Score
Possible issue	Add null check to prevent NullPointerException when comparing string values Add null check for requestedRpaType before using equals() to avoid potential NullPointerException in the RPA conflict check. java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java [117] -boolean conflict = requestedRpaType.equals(existingRpaType); +boolean conflict = requestedRpaType != null && requestedRpaType.equals(existingRpaType); Apply this suggestion Suggestion importance[1-10]: 9 Why: This is a critical fix to prevent NullPointerException in production code. The current implementation assumes requestedRpaType is non-null, which could cause runtime crashes.	9
	Implement retry mechanism with timeout to prevent infinite loops during slot selection Consider adding a maximum retry count or timeout mechanism when searching for available slots to prevent potential infinite loops in case of continuous conflicts. java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java [60-67] -return nodes.stream() +private static final int MAX_RETRIES = 3; +int retryCount = 0; +Set<SlotId> selectedSlots; +do { + selectedSlots = nodes.stream() .filter(node -> { boolean hasCapacity = node.hasCapacity(capabilities, slotMatcher); if (!hasCapacity) { LOGGER.log(Level.WARNING, "Node {0} does not have capacity for capabilities: {1}", new Object[]{node.getNodeId(), capabilities}); } return hasCapacity; }) + ... + .collect(toImmutableSet()); + retryCount++; +} while (selectedSlots.isEmpty() && retryCount < MAX_RETRIES); Suggestion importance[1-10]: 3 Why: While the suggestion aims to prevent potential infinite loops, the current stream-based implementation already handles this efficiently. The suggested change adds unnecessary complexity without clear benefits.	3
General	Use appropriate logging levels to maintain clear distinction between warnings and routine information Consider using a more appropriate log level (INFO or FINE) for routine slot evaluation messages instead of WARNING, which should be reserved for actual warning conditions. java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java [82] -LOGGER.log(Level.WARNING, "Evaluating Node: {0} with load: {1}", new Object[]{node.getNodeId(), node.getLoad()}); +LOGGER.log(Level.FINE, "Evaluating Node: {0} with load: {1}", new Object[]{node.getNodeId(), node.getLoad()}); Apply this suggestion Suggestion importance[1-10]: 5 Why: Using appropriate log levels improves log clarity and helps in debugging. While not critical, it's a good practice that enhances system maintainability.	5